
$QVZHUSRLQWHUV
Section 12.2.1
1. employeeNo, carNo.
2. The attributes in the Car table type would be the same as those in the Employee
table type in Fig. 12.1, so the only difference is that an entity would be thought of as a
car with employee attributes, rather than an employee with car attributes. Most people
would prefer the latter view.
Section 12.2.2
1. Because the participation of Car is obligatory, but that of Employee is non-
obligatory. Consequently, if carNo were posted to Employee, some employee
occurrences would contain nulls. Posting employeeNo to Car does not suffer from this
disadvantage because every car is used by an employee, so the ...